This invention relates generally to intravenous (IV) catheters, and, in particular, to a safety IV catheter in which the needle tip is automatically covered after needle withdrawal to prevent the healthcare worker from making accidental contact with the needle tip.
IV catheters are primarily used to administer fluids, sometimes containing medications, directly into a patient""s vascular system. The catheter is inserted into a patient""s vein by a healthcare worker by using a handheld placement device that includes a sharp tip needle. The needle is positioned in the interior hollow portion of the catheter with its tip extended slightly beyond the edge of the catheter. The end of the apparatus opposite the needle tip is made up of the needle connected to a needle hub which is capable of being held by the healthcare worker during the insertion procedure.
The insertion procedure contains four basic steps: (1) the healthcare worker inserts the needle and catheter together into the patient""s vein; (2) after insertion into the vein with the needle point, the catheter is forwarded into the vein of the patient by the healthcare worker pushing the catheter with his or her finger; (3) the healthcare worker withdraws the needle by grasping the hub end (opposite the point end) while at the same time applying pressure to the patient""s skin at the insertion site with his or her free hand; and (4) the healthcare worker then tapes the now inserted catheter to the patient""s skin and connects the exposed end of the catheter (the catheter hub) to the source of the fluid to be administered into the patient""s vein.
The problem is that, immediately after the withdrawal of the needle from the patient""s vein, the healthcare worker, who is at this time involved in at least two urgent procedures, must place the exposed needle tip at a nearby location and address the tasks required to accomplish the needle withdrawal. It is at this juncture that the exposed needle tip creates a danger of an accidental needle stick occurring, which, under the circumstances, leaves the healthcare worker vulnerable to the transmission of various dangerous blood-borne pathogens, including AIDS and hepatitis.
This danger to the healthcare worker from accidental needle sticks has caused an impetus for the development of a safer IV catheter in which the occurrence of such accidental needle sticks is prevented. Safety catheters that have been developed to achieve this result are disclosed, for example, in Lemieux Reissue U.S. Pat. No. Re. 34,416, Crawford U.S. Pat. No. 5,558,651, McLees U.S. Pat. No. 5,135,504, Gaba U.S. Pat. No. 5,697,907, and Dombrowski U.S. Pat. No. 4,978,344. Kulli U.S. Pat. No. 4,929,241 and Chamuel U.S. Pat. No. 5,053,107 disclose a protective needle guard for use with a hypodermic needle.
The prior art safety catheters all exhibit one or more drawbacks that have thus far limited their usefulness and full acceptance by healthcare workers. For example, in the safety catheter disclosed in the Lemieux patent, the force required to engage the needle slot within the guard flange is relatively great and would interfere with the removal of the needle. Reducing this force to a more acceptable level would create the possibility of the needle guard remaining in the catheter hub after the needle is removed from the catheter. As a result, the safety catheter disclosed in the Lemieux patent would not consistently function in a reliable manner.
Similarly, the user of the safety catheter disclosed in the Dombrowski patent would have to exert a considerable force to remove the protective cap from the catheter hub when the cap engages a needle. The safety catheter disclosed in the Dombrowski patent would also be relatively expensive to fabricate because of its inclusion of a flexible flange and a tether.
The McLees protective device requires an irksome extra pulling action or tug on the needle guard through a retention ring to remove the protected needle from the catheter hub. The McLees device also requires the assembly of two separate components and is thus relatively costly to manufacture. In addition, the needle in the McLees device includes a larger diameter portion near and at the needle tip. This feature of the McLees device would require that the remainder of the needle be of a lesser diameter which would have the adverse effect of slowing the blood flashback through the needle.
It is accordingly an object of the present invention to provide a safety IV catheter which reliably and automatically prevents accidental, inadvertent contact with the needle tip after use.
It is a further object of the invention to provide a safety catheter which provides reliable protection to the healthcare practitioner against needle sticks without requiring any change in the manner of use of the safety catheter by the practitioner.
It is another object of the present invention to provide a safety IV catheter of the type described which is relatively simple and inexpensive to manufacture.
It is yet a further object of the present invention to provide a safety catheter of the type described in which removal of the needle from the needle guard after use is prevented.
To these ends, the safety IV catheter of the invention includes a resilient spring clip needle guard that includes a distal or front end and a proximal or rear wall. The spring clip is inserted into the catheter hub and is urged by the needle shaft into contact with the inner walls of the catheter hub so that the needle guard is reliably retained therein. When the needle is withdrawn from the catheter, the force it had previously exerted on the needle guard is released, causing the needle guard to pivot within the catheter hub until it clamps onto the needle shaft. At this time, the distal end wall of the needle guard blocks the distal pointed end tip of the needle. In addition, the spring clip and protected needle onto which it is clamped can be readily and safely removed from the catheter hub. The needle may be provided with a slot or, alternatively, may be provided with a segment of increased width, such as a crimp, which cooperates with the needle guard to prevent the inadvertent removal of the needle from the needle guard after their removal from the catheter hub.
In another embodiment, an IV catheter apparatus is provided which comprises a tubular catheter having a proximal end and a distal end and a needle having a needle shaft and a tip, where the needle is received within the tubular catheter when in a ready position. A catheter hub is attached to the proximal end of the catheter, where the catheter hub has a hollow interior and an inner wall. The needle is movable between the ready position, in which the tip is outside of the catheter hub, and a retracted position, in which the tip is within the interior of the catheter hub. A unitary needle guard is positioned in the interior of the catheter hub and includes a resilient portion engaged by the needle shaft when the needle is in its ready position. A section of the resilient portion of the needle guard is urged by the needle shaft into contact with an interior wall of the catheter hub when the needle is in its ready position. An inwardly extending annular protrusion is formed on the interior wall of the catheter hub for engaging a segment of the needle guard for retaining the needle guard in the catheter hub during the movement of the needle between its ready position and its retracted position. The needle guard includes a distal wall extending from the resilient portion and spaced from the needle tip when the needle is in its ready position and movable within the interior of the catheter hub to a blocking position distal of the needle tip when the needle is in its retracted position in which the needle shaft no longer exerts a force on the resilient portion of the needle guard, such that contact between the segment of the needle guard and the catheter hub is released.
In another embodiment of the spring clip safety catheter of the invention, a retaining groove or bump is formed in the inner wall of the catheter hub, which, in the ready position, engages a lower arm of the spring clip to aid in the retention of the spring clip in the catheter hub.
In yet a further embodiment of the spring clip safety catheter of the invention, a slot is formed in the needle. After the spring clip has pivoted to its retracted position and the needle is clamped by the spring clip, further movement of the needle in the proximal direction will cause the rear or proximal arm of the spring clip to seat in the slot, thereby to more securely clamp the needle shaft to the spring clip.
In a further embodiment of the spring clip catheter guard of the invention, a tether is connected to the needle hub and the spring clip guard to prevent the spring clip guard from being pulled off the protected needle without requiring an excessive clamping force therebetween.
In yet a further embodiment of the invention, the spring clip needle guard is in the form of resilient intersecting arms, each terminating at a distal guard wall. When the needle is in the ready position, it passes through the guard and urges the resilient arms away from each other and against the inner wall of the catheter hub. When the needle is retracted past the guard walls, the resilient arms spring to the safety position in which both of the guard walls are positioned distally from the needle tip, thereby to form a barrier that prevents inadvertent contact with the needle tip.